The four sentences (labelled 1, 2, 3 and 4) given below, when properly sequenced, would yield a coherent paragraph. Decide on the proper sequencing of the order of the sentences and key in the sequence of the four numbers as your answer.

1. Centuries later formal learning is still mostly based on reading, even with the widespread use of other possible education-affecting technologies such as film, radio, and television.

2. One of the immediate and recognisable impacts of the printing press was on how people learned; in the scribal culture it primarily involved listening, so memorization was paramount.

3. The transformation of learners from listeners to readers was a complex social and cultural phenomenon, and it was not until the industrial era that the concept of universal literacy took root.

4. The printing press shifted the learning process, as listening and memorisation gradually gave way to reading and learning no longer required the presence of a mentor; it could be done privately.

The correct sequence of the sentences to form a coherent paragraph is 2431.

Let us analyze the logical connection between the sentences step-by-step:

1. Sentence 2 is the ideal opening sentence because it introduces the central theme: the impact of the invention of the printing press on how people learned. It establishes the baseline of the pre-printing era ("scribal culture"), where learning primarily involved listening and memorization.

2. Sentence 4 logically follows Sentence 2. It elaborates on the immediate shift caused by the printing press, explaining how listening and memorization (mentioned in Sentence 2) gave way to reading, which allowed for private learning without requiring a mentor.

3. Sentence 3 expands on this shift, describing the transition of learners from listeners to readers as a complex social and cultural phenomenon. It moves the timeline forward to the industrial era, when universal literacy finally took root.

4. Sentence 1 concludes the paragraph by bringing the discussion to the present day ("Centuries later"). It states that formal learning is still heavily reliant on reading, despite the advent of modern technologies like film, radio, and television.

Therefore, the logical flow is 2 → 4 → 3 → 1.